Crackling Blade

You brandish the weapon used in the spell's casting and make a melee attack with it against one creature within 5 ft. of you. On a hit, the target suffers the weapon attack's normal effects, and then becomes wreathed in crackling energy until the start of your next turn. If the target uses it's Reaction before then, the target takes 1d8 Lightning damage, and the spell ends.

Cantrip Upgrade. The spell's damage increases when you reach certain levels. At Level 5, the melee attack deals an extra 1d8 Lightning damage on a hit, and the damage the target takes for using it's Reaction increases to 2d8. Both damage rolls increase by 1d8 at Level 11 (2d8 and 3d8), and again at level 17 (3d8 and 4d8).